Fix tab backgrounding on Linux / ChromeOS

content/browser/renderer_host/render_process_host_browsertest.cc

Index: content/browser/renderer_host/render_process_host_browsertest.cc
diff --git a/content/browser/renderer_host/render_process_host_browsertest.cc b/content/browser/renderer_host/render_process_host_browsertest.cc
index 941371c205b6a40ec54b5ee8dc58426208c71266..773b05762fb6b358f3fa305b59cc25c16ce92600 100644
--- a/content/browser/renderer_host/render_process_host_browsertest.cc
+++ b/content/browser/renderer_host/render_process_host_browsertest.cc
@@ -4,12 +4,15 @@
 
 #include "content/browser/renderer_host/render_process_host_browsertest.h"
 
+#include "base/bind.h"
 #include "base/command_line.h"
+#include "base/process.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/common/test_url_constants.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/common/content_switches.h"
 
 RenderProcessHostTest::RenderProcessHostTest() {
@@ -28,6 +31,26 @@ int RenderProcessHostTest::RenderProcessHostCount() {
   return count;
 }
 
+void PostQuit(MessageLoop* loop) {
+  loop->PostTask(FROM_HERE, new MessageLoop::QuitTask);
+}
+
+void DoNothing() {}
+
+base::ProcessHandle RenderProcessHostTest::ShowSingletonTab(const GURL& page) {
+  browser()->ShowSingletonTab(page);

[Ben Goodger (Google), 2011/12/02 00:05:04]

Can you achieve this by using a different Browser method?

Reason is, content-team is working on breaking the dependency between content
browser tests and chrome. This will mean they eventually get rid of access to
browser() from these tests. They will have to port tests to use only types
available in src/content. For simple operations like opening a new tab, these
are more straightforward to port, since they can just create a new TabContents
instead of bouncing through Browser.

But this API, ShowSingletonTab, is very Browser-specific and it'd be good if we
could avoid it.

+  TabContents* tc = browser()->GetSelectedTabContents();
+  CHECK(tc->GetURL() == page);
+
+  // Ensure that the backgrounding / foregrounding gets a chance to run.
+  content::BrowserThread::PostTaskAndReply(
+      content::BrowserThread::PROCESS_LAUNCHER, FROM_HERE,
+      base::Bind(DoNothing), MessageLoop::QuitClosure());
+  MessageLoop::current()->Run();
+
+  return tc->GetRenderProcessHost()->GetHandle();
+}
+
 IN_PROC_BROWSER_TEST_F(RenderProcessHostTest, ProcessPerTab) {
   // Set max renderers to 1 to force running out of processes.
   content::RenderProcessHost::SetMaxRendererProcessCountForTest(1);
@@ -84,6 +107,42 @@ IN_PROC_BROWSER_TEST_F(RenderProcessHostTest, ProcessPerTab) {
   EXPECT_EQ(host_count, RenderProcessHostCount());
 }
 
+// We don't change process priorities on Mac or Posix because the user lacks the
+// permission to raise a process' priority even after lowering it.
+#if defined(OS_WIN) || defined(OS_LINUX)
+IN_PROC_BROWSER_TEST_F(RenderProcessHostTest, Backgrounding) {
+  if (!base::Process::CanBackgroundProcesses()) {
+    LOG(ERROR) << "Can't background processes";
+    return;
+  }
+  CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
+  parsed_command_line.AppendSwitch(switches::kProcessPerTab);
+
+  // Change the first tab to be the new tab page (TYPE_WEBUI).
+  GURL newtab(chrome::kTestNewTabURL);
+  ui_test_utils::NavigateToURL(browser(), newtab);
+
+  // Create a new tab. It should be foreground.
+  GURL page1("data:text/html,hello world1");
+  base::ProcessHandle pid1 = ShowSingletonTab(page1);
+  EXPECT_FALSE(base::Process(pid1).IsProcessBackgrounded());
+
+  // Create another tab. It should be foreground, and the first tab should
+  // now be background.
+  GURL page2("data:text/html,hello world2");
+  base::ProcessHandle pid2 = ShowSingletonTab(page2);
+  EXPECT_NE(pid1, pid2);
+  EXPECT_TRUE(base::Process(pid1).IsProcessBackgrounded());
+  EXPECT_FALSE(base::Process(pid2).IsProcessBackgrounded());
+
+  // Navigate back to first page. It should be foreground again, and the second
+  // tab should be background.
+  EXPECT_EQ(pid1, ShowSingletonTab(page1));
+  EXPECT_FALSE(base::Process(pid1).IsProcessBackgrounded());
+  EXPECT_TRUE(base::Process(pid2).IsProcessBackgrounded());
+}
+#endif
+
 // When we hit the max number of renderers, verify that the way we do process
 // sharing behaves correctly.  In particular, this test is verifying that even
 // when we hit the max process limit, that renderers of each type will wind up